list_prefectures

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations provided, so the description carries full burden. It only states the return type (dictionary of names and codes) but does not disclose behavior such as whether it requires authentication, if the list is static or dynamic, or any side effects. More detail on the return structure or scope would improve transparency.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, no fluff. The purpose is stated upfront, and the return format is clearly described in the second sentence. Every word is essential.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with no parameters and a simple list output, the description is mostly complete. It specifies the output type. However, it could mention whether the list covers all regions or a specific country (implied by 'prefecture', likely Japan). The existence of an output schema helps, so this is not critical.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool has zero parameters, so the schema fully covers input. The description adds value by specifying the output format (dictionary of names and codes), which is helpful for understanding what the tool returns. Based on guidelines, baseline is 4 for zero parameters.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the verb 'list' and the resource 'all available prefecture codes for weather forecast'. It is specific and distinguishes from sibling tools which are weather data retrieval and station search.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance on when to use this tool versus alternatives like getting weather by location or station info. The description does not mention prerequisites, typical workflow, or scenarios where this tool is appropriate.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.